Processing sugar



Oct. 20, 1942. J. J. NEUMAN PROCESSING SUGAR 2 Sheets-Sheet l Original Filed March 24, 1939 nm ml llllllllllllll|- I MiaN-roa 39.00%3- NE! Oct. 20, 1942. J. J. NEUMAN PROCESSING SUGAR 2 Sheets-Sheet 2 Original Filed March 24, 1939 Inn-ml m I 1 1 ,1 w.

uwavrrow. 1mm:- Neuvwwl Pn' TORNE steps of the processing operations.

Patented Oct. 20, 1942 PROCESSING SUGAR.

Jacob J. Nenman, South Salem, N. Y., assign: to United States Patent Development and Royalty Company, South Salem,

New York N. Y., a company oi Original application March 24, 1939. Serial no. 263,974. Divided and this application June 8,

1939, Serial No. 277,989

2 Claims.

The present invention relates to improvements in apparatus and method for processing sugars and the like and relates more particularly to an improved apparatus and method for heating and conditioning sugar magmas and other sugar liquor mixed with crystal or granular sugar, as well as similar mixtures, which exist in various This application is a division of my co-pending application Serial No, 263,974 filed March 24, 1939.

It has for its primary object the heating and mixing of the material during-it's transfer from one location to another and without appreciable collecting or adherence of the material to the heating surfaces.

In order to make the advantages of this new method of processing clearly understood a brief description of the first few steps in the refining process of beet and cane sugar and the difficulties experienced with present methods will be given. The raw sugar in crystal form is the initial condition of the sugar. Each crystal has a thin coating of molasses and other uncrystallizable matter, according to the completeness of the previous sugar making process complementary to the extraction of the sugar from the original cane or beets. It is the purpose of these primary processing steps; which are described below, to remove this coating of molasses and other syrups leaving the sugar crystals in as nearly a pure state as possible. The primary difliculty experienced consists in removing a maximum amount of said molasses and syrups without at the same time removing any of the sugar crystal itself. With present methods a considerable portion of the sugar crystal is dissolved along with the molasses and syrup and it is a primary object of my invention to obviate this condition.

In the present methods of separation, the raw sugar-is mixed with an afllnation syrup (usually called greens, syrup or molasses) which also contains a considerable amount of uncrystallizable material The result of this mixing is to coat the raw sugar crystals with this liquid making a heavy, sluggish mixture hereafter called magma. Obviously, this magma if kept fairly hot will have a much lowerviscosity than otherwise, thus being easier to handle and separate. Therefore, heated 'afllnation syrup is used enabling the initial mixing to be accomplished more easily and requiring less greens to be used to attain the desired viscosity.

At present this heating is accomplished by raising the temperature of the aifination syrup to about 180 to 190 F. and mixing it with cold raw sugar in conveyor screws. The final temperature of the resulting mixture, hereafter referred to as magma, being about to F. Due to the fact that it is inherently impossible to introduce the hot afilnation syrup in such a manner that it will immediately contact all of the, cold raw sugar, it is obvious that portions of the raw sugar are momentarily heated to temperatures approaching F. when initially contacted by this hot syrup. This results in melting of the sugar crystals. The crystals so melted do not recrystallize when the mixture attains its final temperature of 120 to 130 F. and since the purpose of the centrifugal extractors in which the magma is subsequently processed, is to separate the solid crystals from the liquids this melted sugar is separated from the solid crytals along with the afllnation syrup and can only be retrieved by several additional and costly processing steps.

With my invention this melting of the sugar crystals is entirely obviated since the amnation syrup initially contacts the raw sugar in a cold condition or in any event at a temperature not exceeding the desired final magma temperature. The mixed afilnation syrup and raw sugar crystals are then brought up to the final temperature together and no part of the mixture ever attains a temperature in excess of this final temperature, A

After the initial greens and raw sugar mixing, called amnation, resultingin the magma, the latter is transferred to a large tank with sloping sides converging downward. In this tank are several longitudinal shafts rotating slowly. These shafts in turn bear paddles or blades which mix the magma constantly and keep it in a uniformly fluid condition always ready for the next processing step. This large tank, called the mixer, also serves as a storage place to take up variations in the rate of introduction of raw sugar and the rate of subsequent operations, The next step in the process consists of centrifuging the magma, thus throwing off all liquids, even the denser ones. After the liquids are about all thrown off, a light spray of warm water is played on the sugar in the centrifugal The washed sugar is now discharged from the centrifugal machine and. falls into a screw con veyor or other suitable means to take it to the next step in the process. The machines, are

ing the greens immediately through a closed heater, where they pass through copper tubes which, in turn, were surrounded by live steam.

aaaaeaa This made the greens hotter and more fluid,

therefore easier to handle as well as putting them in the proper condition for making more magma since most of the greens thus heated is usually led back to the initial step of mixing the greens and raw sugar. However, the difficulty with this type of heater has been that the tubes quickly become clogged, due to the nature of the gree and require frequent cleaning.

The washed sugar is quite d y when plowed out of the, centrifugal machine. In order to facilitate handling and at the same time prepare this washed sugar for subsequentsteps'in the refining process, it is mixed with water and heated by live steam in open heaters. The water used is usually sweet water" resulting fromthe rinsing of various sugar tanks and machinery. It is clean water having dissolved in it a;small amount of sugar. The utilization of this sweet melting of the sugar crystals due to the uneven heating.

It is {also a further object of the invention to provide a system where the heating medium isutilized in the various steps in such a manner that a maximum portion oi its original heat energy is utilized. g

Another important object is to permit utilization of the surplus sweet water, previously men'- tioned, in the dilution of the liquors or mixtures, instead of the present practice .of using the condensate from the live steam used in the open heaters or so-called melters;

4 In addition, there are other objectives such as i the elimination of separate heating steps: for the v greens" used in the initial preparation of the magma; for the washed sugar liquor before pumping away to the next step of the refining process; and for the greens as thrownofl from the centrifugal extractors. Other objects of the invention will be evident in the following description of the-raw sugar treatment as carried on with this invention incorporated in the various steps of the process. v

With the foregoing and other objects in view, the invention will be more fully described hereinafter, and will be more particularly pointed out g in the claims appended hereto.

water is very important, as there is no ther way -most easily handled by the pumps and filters when kept at temperatures avlittle below boiling.

'Eflicient methods are always desirable to maintain the temperature approximately constant without adding steam, asthe steam condensing on contact with the liquor adds this condensate to .the liquor, thus decreasing the density. The maintenance cost of conventional heating equip- -ment to perform this task is high due to the slow accumulation of solid matter on the heat transfer surfaces congealing due to excessive local temperature, which tends to burn or caramelize the sugar of the liquor. The collected deposits must be cleaned of! periodically not only to keep the equipment in efiicient operation but to keep all old or stale material out of the various parts to co which must he met in the various food industries.

It is thus seen that at several steps in the process it is necessary to heat the' material being processed and that, at present, this heating is variously accomplished by the use of live steam in open heaters and by stationary coils in closedheaters and is attendant with many dimculties.

It is, therefore, a primary object of this invention to provide a heating means designed to overcome these difflculties namely: dilution of.

liquors dueto condensed steam, clogging of heatdesignates generally-a ra o. ly with sanitary standards I In the drawings, wherein like symbols refer to like or corresponding parts throughout the several views. j m Figure" 1 is a vertical sectional view taken through an apparatus constructed according to. the present invention. k Figure 2 is an enlarged longitudinal sectional view taken through a shaft and its connections and showing an improved arrangement of packing. s i

Figure 2* is a view similar to Figure 2 showing a slight modification.

Figure 3 is a side elevation of a half section'of conveyor or screw flight showing one method of formation of the same.

Figure 4 is an edge view taken from the inner edge of said'fiight. r m

, Figure 5 is a cross-section taken through one of, the flights and showing a method of attachment to the shaft and tea reinforcing and bearing band. i 0

Figure 6 is an end view of ,a form of hollow paddle employed. Figure '7 is a side view of the same, and Figure 8 is an enlarged fragmentary side view of the raw-sugar melting screw with parts broken away and parts shown in section.

- Referring more ly in .Figure 1, i sugarmingler or the trough constituting the same which is supplied with the raw sugar 2 by conveyor 3 from a suitablesource of supply. a a In the trough l is a spiral or screw conveyor. driven by the electric or other motor 4 through appropriate transmission connections, the screw being rotated in such a sense or direction that it will advance the material in the trough! toward the left where the same will flow over the baffle 5 and be delivered to the tank a which is designated as the magma mixer. -In this tank ers due to caramelization of sugar on coils and is a spiral conveyor or screw I rotated by a motor 8 through the connections indicated for the purpose of advancing the material to "the spouts ll by which the same is delivered to the centrifugal extractors 9. Sweet water is delivered to the extractors by the connection II from the source of supply or header l2.

The separated sugar from the extractors I is delivered to the trough ll of the raw sugar melting screw H to which sweet water is admitted by a pipe I from the header If. The screw header 25 and to a pipe 24 which conveys the hollow screw l1 and to the hollow shaft of the, hollow screw 21.

A steam pipe 35 connects the opposite ends of the shaft of the greens screw 21 with one end I of the hollow shaft of the magma mixer hollow screw 1, the other end of this screw 1 being connected with a pipe 33 which conveys the steam to one end of the hollow shaft of the raw sugar mingler I. The other end of the hollow shaft of mingler I being connected to an exhaust header 34.

The end of the hollow melting screw I1 communicates with condenser chamber 66 connected by pipe 1| with a steam trap 59 also connecting with pipe 33.

Discharge end of hollow melting screw l1 projects through and has a bearing upon disc 10 mounted upon the shaft of the screw H. The disc 10 has a broad rim 53 rotating in flanged guide 51 carried by the casing of the condenser chamber 55.

At the right hand end of melting screw trough l1 and below greens tank 23 is the raw sugar liquor tank 42 disposed to receive the liquor which is caused to overflow baflle l8 by the action of screw H. A screen 4| guards the entrance to the raw sugar liquor tank 42 from which, by means of a pump 43, the raw sugar liquor is delivered to the header or destination.

Referring more particularly to Figure 2, a fragmentary end portion of a hollow shaft 5| is shown which sh'aft might be the shaft of any one of the screws. For example, shaft 5| is denominated the shaft of the conveyor 1. The wall of the magma mixer through which the shaft passes is designated at; 50. At the outer open end of shaft 5| is secured by appropriate fastenings 15 a disc 52 through which loosely passes the nipple 53. In Figure 1 this nipple 53 is shown as coupled to an elbow 15 by which connection is made to'the flexible hose or other pipe 35. Gaskets 54 extend about the nipple 53 on opposite sides of the disc 52. A coil spring 55 surrounds the nipple 53 within the protection of the end of the hollow shaft 5| and bears at one end against the inner of the gaskets 54 urging such gasket 54 yieldingly up against the inside face of disc 52. At its other end the coil spring tends to expand against a ring 55 which engages one of two or more packing rings 51. The coil spring 55 in effect expands the packing rings 51 between the rings 55 and 58, the latter being afllxed upon the inner end portion of the nipple 53.

Inside of the tank wall 53. a sleeve 53 of greater diameter than. the external diameter of shaft 5| surrounds a-portion of the shaft and may be afllxed at one end to wall 53. At its other end the sleeve carries a disc 11 held in place by appropriate fastenings 13. Packing rings 13 in any suitable numbers. are interposed between disc 11 and the follower ring 35 against which presses at one end a coil spring ll abutting at its other end against wall ill.

Compression of the packing rings causes the same to expand radially. The rings 51 positioned between nipple 53 and the internal annular wall of hollow shaft 5|; while the packing rings 19 expanding between the shaft 5| and the sleeve 59 prevent leakage from the magma mixer about the-shaft out through the opening from which protrudes the end of the hollow shaft 5|. The nipple 53, communicating as it does with the steam supply pipe 35, leads steam or hot vapor into the 'endof hollow shaft 5| and the packing 51 prevents this steam from leaking out around the-exterior of the nipple 53. These packing rings 51, positioned as shown and desojribed remote'from the disc 52 and gaskets 54, enable a loose fit of the nipple 53 to take care of conditions of variation in correct alinement.

This Figure 2 therefore shows one method of making avfluid path connection to an end of the rotating screw shaft 5|. The gaskets or collars 54 are tightly fitted on the pipe nipple 53. The pipe nipple '53 is positively held in pomtion against a longitudinal or axial motion by the disc 52 and collars 54. The packing 51 always being compressed by the spring 55 maintains a tight joint between the moving or rotating hollow shaft wall 5| and the stationary pipe nipple 53.

Referring more particularly to Figures 3 and 4, there is here shown one form of flight of which the various screws may be made. These figures show a section of the flight as made in one piece of cast steel. The edges 32 and 83 are bevelled to permit good welds to be made when being fabricated on the hollow shaft, for instance the hollow shaft 5| of Figure 2. Similar pieces may also be easily made from flat plates warped to the shape shown and welded together at the vertex of the V. This vertex is designated at 84. Also similar cast plates may be made with ears, such as the ears 85, shown in Figure 5, provided to fltagainst the shaft, such as the shaft 5|, whereby bolts, screws or other fastenings may be employed instead of welding the flights to the hollow shaft. Ears might also be provided for joining of adjacent sections of the flights when installing whereby bolts could be used throughout and welding on the job eliminated. Such an installation would simplify replacement of one or more sections of hollow flight when necessary without resorting to the burning and welding which would otherwise be necessary in the case of flights fabricated by welding.

Referring more particularly to Figure 5, I have here shown a sectional view of a flight unit 6| which is the central flight unit, for instance of the raw sugar mingler The hollow flight BI is cast or built up by welding, or otherwise,

with bracket 52 on the peak of the V. Suitable holes, either threaded o1- drilled through, are provided for the fastening in place of the cylindrical collar 63 by thefastenings 54. This collar 63 is of a diameter slightly larger than the screw 33 in the raw sugarmingler- I, and is of a suitable low friction metal .so that when engaged in a cooperating part ,81 of the stationarytrough I localized resistance of the screw flights to tumwazsaeaathe centrifugal extractors 3 through the spouts I; Herethe'magma is centrifuged, the fluid Y ing. By using a large diameter hollow shaft and with-the flights thereon to support this shaftin the manner of a truss, it is not likely that an intermediate bearing for the rotating part will be necessary in the installation.

Referring more particularly to Figures 6 and 7,

I heating medium. Whenevernolongitudinal movement of the substance being heated isdesired the paddle type of heater 81' might be used exclusiveiy.

In operation, the sugar from the storage bins or bag dump (not shown) is conveyed by the conveyor 3 to the raw sugar mingler I. Hot water flows upwardly throughpipe 33 and into the left hand end of the hollow shaft of the mingler screw 86. This hot water circulates through the hollow flights 86 and through the hollow paddies 81' and passes out into the low temperature water line 34. It will be noted that the hot water flows in a direction from left to right through the hollow shaft and hollow screw 86 which thus becomes a heating element and also a screw conveyor; while the sugar material 2 is advanced by the spiral conveyor or screw from right to left. The counterflowfprinciple herein applied per mits the mixed magma flowing over the baflle 5 to have become heated to ,nearly the temperature of the water supplied to the heating element or screw and its shaft. Suitable consistency of greens is supplied to the mingler through the line 24 from the greens pump 26 when there is a suflicient quantity being pumped; otherwise from the main greens header 25, such as when starting operations. This greens will of course have a temperature according to that of the greens header 25, except as reduced by temperature drop in the long connecting pipe line 24. e

The raw sugar and greens having been thoroughlymixed in the raw sugar mingler I by the action of the conveyor, and also by the paddles 31' if used, the resulting magma is discharged over the end baille '5, falling into the mixer 6. Here the heated screw conveyor 1 rotates slowly, keeping the mixturein a proper condition. It is necessary to maintain this mixing motion at all times, as two or three hours without mixing would permit the magma tobecome sluggish or almost set, and the mixerscrew could not be "started up again.

This conveyor 1 receives its heating water through the pipe line 35 from the greens screw 21 and the flights 'of the conveyor 1 are also preferably hollow.

From time to time the magma is drawn oil. into portion being thrown off and drained away in the trough 2|. Also during the spinning a small amount of sweet water is sprayed upon the whirling magma by suitable spray nozzles II. This spray water also is' forced on completing the washing of the sugar,- after which the machine is'slowed down and the washed sugar plowed out through the bottom openings l4 into the raw 7 sugar melting screw trough IS.

The raw sugar melting screw l1 turns fairly rapidly and mixes the washed sugar from the,

centrifugal extractors with sweet water from the main sweet water header i2 flowing into-the screw I! by means of pipe ii. The heatedscrew conveyor I1 is heated by steam entering at the discharging end being fed in through the pipe 32' from the steam header 3|. Thesteam flows into the heater element flight II, where it com.-' pletely condenses in heating up the raw sugar and sweet water mixture being agitated together in the raw sugar melting screw trough IS; the screw tending to move the mixture toward the discharge end baflle l8. v

The raw sugar, properly washed and discharged into the raw sugar melting screw trough i5, mixes with a suitable'amount of sweet water supplied from the pipe i6 to form a smoothly running liquor by the time it has been worked along the trough 20 by the heated screw conveyor 11. The sweet water supplied is adjusted to insure complete dissolving of the sugar before it leaves the melting screw trough l5 over the baille l8. This raw sugar liquor then passes through the screen 4! to the raw sugar liquor tank 42, from which heat, to be absorbed by the raw sugar melting into the sweet water. r

The screw installation for the raw sugar melting screw I! has incorporated in it if-desired the special type of flightshown in detail in Figures 3 and 4. v

The left end of the screw iI opens directly into chamber 66 where such end is fitted through the disc Ill which'seals the trough compartment I5 from the chamber 66. The cylindrical bearing strip 68 which rotates with the heater element screw assembly I! may be firmly attached thereto by suitable bolts or cap screws which allow replacement as might be needed. The chamber 86 is thus completely sealed off from the main trough compartment I5 by means of the end disc 10, the

bearing strip 68 mounted on the rotating part II and the cooperating stationary part 61 mounted in the frame of the main trough l5 atathe left end thereof. The closed chamber'SG drains by means 'of the connecting pipe Ii into the steam trap 69 which will pass water from the chamber 66 into the hot water pipe 33 but will not allow any steam to pass into this pipe 33 from the chamber 66.

' During the operation of the raw sugar melting screw II, the steam entering the hollow shaft by means of the pipe 32 from the steam header forces this condensate along and out of the open end of the flight IT to the chamber 68 together with some occluded and live steam which failed to condense. The condensate collects in the bottom of the chamber 66 and is forced out through the steam trap 69. When an excess of steam collects within the chamber 66, the pressure built up will retard the flow of additional steam into the hollow flight I! from the steam header 3|. This will permit more complete condensation of the existing steam within the flight l1 until the pressure in the chamber 66 is again reduced to lower value which will permit more live steam to enter. This is a suitable governor for the regulation for the steam entering the moving or rotating heater element I1 and is desirable to prevent waste of steam and overheating of the raw sugar liquor. V

The use of this method of providing a path for fluid flowing from the moving heater element flight I! to the external stationary pipe installation also provides an alternative installation method, eliminating the packing gland of Figure 2 at this end of the hollow shaft. At the same time it provides a bearing for the moving element to rotate upon, which in some instances would be a distinct advantage in providing additional shaft support.

The greens, namely the liquid portion of the magma thrown oil by the centrifugal extractors 9 and the spray water used in the said extractors 9, drain away in the trough 2|, collecting in the greens screw 22. Here the greens absorb heat from the heated screw conveyor 21 which is heated by steam flowing from the steam main 3| through the pipe 32 and 32 into the heater element flight at the discharge end of the greens screw 22. As explained in the case of the raw sugar melting screw H, the counterflow principle operates to bring the greens up to a suitable temperature by bringing about a large amount of heat transfer to the latter.

The greens flows from the discharge end of the greens screw 22 through the screen 28 into the greens tank 23, from which it is pumped into the main greens header 25 by the steam pump 26, except that a, sufllcient amount of the greens is led through the pipe 24 back to the raw sugar mingler to take part in the aflination process there.

It is to be understood that the heating fluid, usually steam or hot water, could be circulated in different ways. Thus, in the winter, steam might be introduced directly to the magma mixer 6 and the raw sugar mingler to keep the temperature high enough. Also instead of heating the various screw heater elements from the plant steam header, hot condensate from various other equipment might be utilized; thus adding to the thermal efliciency of the system. Possibly the greens heating screw 22 would be constructed using a long moving heater element screw conveyor rotating in a large diameter pipe to insure thorough mixing and keep the entire heating surface almost totally immersed in the greens. The drawing shows a short section thus arranged.

Sometimes it is found desirable to add sweet water to the greens in order to decrease the density to allow proper fluidity to permit pumping and the like. Under the conditions of combined uses it might be desirable to heat the sweet water supply.

In Figure 2' the packing rings 19 are disposed against the wall ill instead of against the disc 11 and the position of the follower ring 80 and the spring 8| is reversed accordingly.

In Figure 8 a portion of the shaft SI of the raw sugar melting screw I1 is shown to more clearly illustrate the internal plug 13 andthe holes or perforations 12 which admit the steam into the hollow flight II.

It will be understood from the foregoing that the condensate from the steam in any or allof the hollow screws or conveyors does not contact the sugar crystals or the magma and therefore this condensate does not have the effect to dilute the melted sugar. For this reason it is possible with this steam to use more sweet water for the purpose of bringing the sugarliquor to proper density. The utilization of as much sweet water as possible at this point in the. process is very important since there is no other way to efllciently reclaim the sugar dissolved therein. Consequently the hollow conveyor, preventing contact between the steam, or its water of condensation, and the sugar or mixture thereof with the greens or affination syrup, is very important as not creating further sweet water and in fact as achieving a recovery of the sugar dissolved in the sweet water in other less eflicient parts of the plant.

It is obvious that various changes and modifications may be made in the details of construction and design of the above specifically described embodiment of this invention without departing from the spirit thereof, such changes and modifications being restricted only by the scope of the following claims.

What is claimed is:

1. In the processing of sugar which consists in in a mingling zone to form a magma, agitating and mixing the magma in a mixing zone, centrifuging the magma to separate sugar crystals from greens, melting the centrifuged sugar crystals in a melting. zone in the presence of sweet water, collecting the separated greens in a storage zone, and returning said greens to the mingling zone as the aflination syrup for admixture with raw sugar crystals; th method of heating the materials in the said several zones to respectively difierent temperatures, which consists in conducting a heating fluid in a stream through the melting zone in indirect contact with the sweet water and sugar crystals of the centrifuge in said zone to maintain a melting temperature of the sugar crystals, simultaneously conducting a second stream of heating fluid through the greens storage zone in indirect contact with the greens in the said zone to reduce the viscosity of the greens before returning said greens to the mingling zone as ailination syrup, conducting one of said streams of heating fluid through the magma mixing zone in indirect contact with the magma in said mixing zone to reduce the viscosity of the magma which is being agitated, combining the first-named stream with the secondnamed stream of heating fluid in a single stream at th resulting mean temperature, and conducting the combined stream through th mingling zone in indirect contact with the raw sugar and aflination syrup in said zone, to maintain a in the magma mixing zone, whereby all of said zones are subjected to heat without dilution of the materials by said heat other than such of the materials themselves.

2. In the processing of sugar which consists in adding an affination syrup to raw sugar crystals in a mingling zone to form a magma, agitating and mixing the magma in a mixing zone, cen- 1 trifuging the magma to separat sugar crystals 1 from greens, melting the centrifuged sugar crys tals in a melting zone in the presence of sweet water, collecting the separated greens in a storage zone, and returning said greens to the min- I glingv zone as the afiination syrup for admixture with raw sugar crystals; the method of heating the materials in the said several zones to respec- 4 temperature in the latter below the temperature a neously conducting a second stream of heating fluid through the greens storage zone in indirect contact with the greens in said zone to reduce th viscosity of thegreens before reducing the greens to the mingling zone asafllnatlon syrup, conducting said second-named stream of heating fluid through the magma mixing zone in indirect contact with the magma while being agitated in said mixing zone to reduce viscosity of the magma, and then conducting the same stream in indirect contact with the sugar crystals and amnation syrup of the mingling zone, and combining said first-named stream with said secondnamed stream of heating fluid before the latter enters the mingling zone to obtain a resulting mean temperature, to maintain a temperature in the latter below the temperature in the magma mixing zone wherebyall of the zones are subjected to indirect heating without dilution of the materials by said heat other than such dilution of the materials themselves.

JACOB J. NEUMAN. 

